TRAC (programming language)

TRAC (for Text Reckoning And Compiling) Language is a programming language developed between 1959-1964 by Calvin Mooers and implemented on a PDP-10 in 1964 by L. Peter Deutsch. It was one of three "first languages" recommended by Ted Nelson in Computer Lib. TRAC T64 was used until 1984, when Mooers updated it to TRAC T84.

TRAC is a purely text-based language—a kind of macro language. Unlike traditional ad hoc macro languages of the time, such as those found in assemblers, TRAC is well planned, consistent, and in many senses complete. It has explicit input and output operators, unlike the typical implicit I/O at the outermost macro level, which makes it simultaneously simpler and more versatile than older macro languages.

It also differs from traditional macro languages in that TRAC numbers are strings of digits, with integer arithmetic (without specific limits on maximum values) being provided through built-in ("primitive") functions. Arguably, one aspect of its completeness is that the concept of error is limited to events like lack of file space and requesting expansion of a string longer than the interpreter's working storage; what would in many languages be described as illegal operations are dealt with in TRAC by defining a result (often a null string) for every possible combination of a function's argument strings.

The emphasis on strings as strings is so strong that TRAC provides mechanisms for handling the language's own syntactic characters either in their syntactic roles or like any other character, and self-modifying code has more the feel of a natural consequence of typical TRAC programming techniques than of being a special feature.

TRAC is, like APL or LISP, an expression oriented language (in contrast to more typical procedure-oriented languages), but unlike APL, it completely lacks operators. In most respects, it is a case of pure functional programming.

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